资料介绍
More and more, battery operated systems are requiring lower
terminal voltages to power internal circuits. Multi-cell designs are
rapidly migrating to single-cell architectures to reduce system cost.
A prime example of this system type is digital cameras, which often
use a single-cell 3.6V Li-Ion battery for their power source. Digital
cameras contain high-speed memory ICs, which require tight
voltage regulation at moderate loads to meet the required timing
parameters of the system. Precision low dropout (LDO) regulator
devices can be used to meet these requirements but in doing so,
the LDO regulators must be able to successfully operate in the
‘dropout’ mode as the battery discharges. Dropout mode is entered
when the input voltage (from the battery source) is equal to the
“nominal output voltage” of the LDO; for example a 3.3V LDO
enters dropout mode when its input voltage at the V
IN
pin is equal
to 3.3V. Minimal output voltage droop and minimal LDO power
dissipation are critical to meeting various system performance
parameters and extending the life of the battery. AN776
DC Performance Comparisons of CMOS vs. Bipolar LDOs when
Operating in "Dropout" (VIN = Nominal VOUT) Mode
Author: Patrick Maresca,
BACKGROUND INFORMATION:
Microchip Technology, Inc. CMOS vs. BIPOLAR ARCHITECTURE
Figures 1A and 1B compare the block diagram for a common
bipolar regulator with that of an equivalent regulator fabricated in
INTRODUCTION
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